/*
 * pseries Memory Hotplug infrastructure.
 *
 * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#define pr_fmt(fmt)     "pseries-hotplug-mem: " fmt

#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/slab.h>

#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/sparsemem.h>
#include "pseries.h"

static bool rtas_hp_event;

unsigned long pseries_memory_block_size(void)
{
        struct device_node *np;
        unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
        struct resource r;

        np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
        if (np) {
                const __be64 *size;

                size = of_get_property(np, "ibm,lmb-size", NULL);
                if (size)
                        memblock_size = be64_to_cpup(size);
                of_node_put(np);
        } else  if (machine_is(pseries)) {
                /* This fallback really only applies to pseries */
                unsigned int memzero_size = 0;

                np = of_find_node_by_path("/memory@0");
                if (np) {
                        if (!of_address_to_resource(np, 0, &r))
                                memzero_size = resource_size(&r);
                        of_node_put(np);
                }

                if (memzero_size) {
                        /* We now know the size of memory@0, use this to find
                         * the first memoryblock and get its size.
                         */
                        char buf[64];

                        sprintf(buf, "/memory@%x", memzero_size);
                        np = of_find_node_by_path(buf);
                        if (np) {
                                if (!of_address_to_resource(np, 0, &r))
                                        memblock_size = resource_size(&r);
                                of_node_put(np);
                        }
                }
        }
        return memblock_size;
}

static void dlpar_free_drconf_property(struct property *prop)
{
        kfree(prop->name);
        kfree(prop->value);
        kfree(prop);
}

static struct property *dlpar_clone_drconf_property(struct device_node *dn)
{
        struct property *prop, *new_prop;
        struct of_drconf_cell *lmbs;
        u32 num_lmbs, *p;
        int i;

        prop = of_find_property(dn, "ibm,dynamic-memory", NULL);
        if (!prop)
                return NULL;

        new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
        if (!new_prop)
                return NULL;

        new_prop->name = kstrdup(prop->name, GFP_KERNEL);
        new_prop->value = kmemdup(prop->value, prop->length, GFP_KERNEL);
        if (!new_prop->name || !new_prop->value) {
                dlpar_free_drconf_property(new_prop);
                return NULL;
        }

        new_prop->length = prop->length;

        /* Convert the property to cpu endian-ness */
        p = new_prop->value;
        *p = be32_to_cpu(*p);

        num_lmbs = *p++;
        lmbs = (struct of_drconf_cell *)p;

        for (i = 0; i < num_lmbs; i++) {
                lmbs[i].base_addr = be64_to_cpu(lmbs[i].base_addr);
                lmbs[i].drc_index = be32_to_cpu(lmbs[i].drc_index);
                lmbs[i].flags = be32_to_cpu(lmbs[i].flags);
        }

        return new_prop;
}

static struct memory_block *lmb_to_memblock(struct of_drconf_cell *lmb)
{
        unsigned long section_nr;
        struct mem_section *mem_sect;
        struct memory_block *mem_block;

        section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
        mem_sect = __nr_to_section(section_nr);

        mem_block = find_memory_block(mem_sect);
        return mem_block;
}

#ifdef CONFIG_MEMORY_HOTREMOVE
static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
{
        unsigned long block_sz, start_pfn;
        int sections_per_block;
        int i, nid;

        start_pfn = base >> PAGE_SHIFT;

        lock_device_hotplug();

        if (!pfn_valid(start_pfn))
                goto out;

        block_sz = pseries_memory_block_size();
        sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
        nid = memory_add_physaddr_to_nid(base);

        for (i = 0; i < sections_per_block; i++) {
                remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
                base += MIN_MEMORY_BLOCK_SIZE;
        }

out:
        /* Update memory regions for memory remove */
        memblock_remove(base, memblock_size);
        unlock_device_hotplug();
        return 0;
}

static int pseries_remove_mem_node(struct device_node *np)
{
        const char *type;
        const __be32 *regs;
        unsigned long base;
        unsigned int lmb_size;
        int ret = -EINVAL;

        /*
         * Check to see if we are actually removing memory
         */
        type = of_get_property(np, "device_type", NULL);
        if (type == NULL || strcmp(type, "memory") != 0)
                return 0;

        /*
         * Find the base address and size of the memblock
         */
        regs = of_get_property(np, "reg", NULL);
        if (!regs)
                return ret;

        base = be64_to_cpu(*(unsigned long *)regs);
        lmb_size = be32_to_cpu(regs[3]);

        pseries_remove_memblock(base, lmb_size);
        return 0;
}

static bool lmb_is_removable(struct of_drconf_cell *lmb)
{
        int i, scns_per_block;
        int rc = 1;
        unsigned long pfn, block_sz;
        u64 phys_addr;

        if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
                return false;

        block_sz = memory_block_size_bytes();
        scns_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
        phys_addr = lmb->base_addr;

        for (i = 0; i < scns_per_block; i++) {
                pfn = PFN_DOWN(phys_addr);
                if (!pfn_present(pfn))
                        continue;

                rc &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
                phys_addr += MIN_MEMORY_BLOCK_SIZE;
        }

        return rc ? true : false;
}

static int dlpar_add_lmb(struct of_drconf_cell *);

static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
{
        struct memory_block *mem_block;
        unsigned long block_sz;
        int nid, rc;

        if (!lmb_is_removable(lmb))
                return -EINVAL;

        mem_block = lmb_to_memblock(lmb);
        if (!mem_block)
                return -EINVAL;

        rc = device_offline(&mem_block->dev);
        put_device(&mem_block->dev);
        if (rc)
                return rc;

        block_sz = pseries_memory_block_size();
        nid = memory_add_physaddr_to_nid(lmb->base_addr);

        remove_memory(nid, lmb->base_addr, block_sz);

        /* Update memory regions for memory remove */
        memblock_remove(lmb->base_addr, block_sz);

        dlpar_release_drc(lmb->drc_index);

        lmb->flags &= ~DRCONF_MEM_ASSIGNED;
        return 0;
}

static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
                                        struct property *prop)
{
        struct of_drconf_cell *lmbs;
        int lmbs_removed = 0;
        int lmbs_available = 0;
        u32 num_lmbs, *p;
        int i, rc;

        pr_info("Attempting to hot-remove %d LMB(s)\n", lmbs_to_remove);

        if (lmbs_to_remove == 0)
                return -EINVAL;

        p = prop->value;
        num_lmbs = *p++;
        lmbs = (struct of_drconf_cell *)p;

        /* Validate that there are enough LMBs to satisfy the request */
        for (i = 0; i < num_lmbs; i++) {
                if (lmbs[i].flags & DRCONF_MEM_ASSIGNED)
                        lmbs_available++;
        }

        if (lmbs_available < lmbs_to_remove)
                return -EINVAL;

        for (i = 0; i < num_lmbs && lmbs_removed < lmbs_to_remove; i++) {
                rc = dlpar_remove_lmb(&lmbs[i]);
                if (rc)
                        continue;

                lmbs_removed++;

                /* Mark this lmb so we can add it later if all of the
                 * requested LMBs cannot be removed.
                 */
                lmbs[i].reserved = 1;
        }

        if (lmbs_removed != lmbs_to_remove) {
                pr_err("Memory hot-remove failed, adding LMB's back\n");

                for (i = 0; i < num_lmbs; i++) {
                        if (!lmbs[i].reserved)
                                continue;

                        rc = dlpar_add_lmb(&lmbs[i]);
                        if (rc)
                                pr_err("Failed to add LMB back, drc index %x\n",
                                       lmbs[i].drc_index);

                        lmbs[i].reserved = 0;
                }

                rc = -EINVAL;
        } else {
                for (i = 0; i < num_lmbs; i++) {
                        if (!lmbs[i].reserved)
                                continue;

                        pr_info("Memory at %llx was hot-removed\n",
                                lmbs[i].base_addr);

                        lmbs[i].reserved = 0;
                }
                rc = 0;
        }

        return rc;
}

static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
{
        struct of_drconf_cell *lmbs;
        u32 num_lmbs, *p;
        int lmb_found;
        int i, rc;

        pr_info("Attempting to hot-remove LMB, drc index %x\n", drc_index);

        p = prop->value;
        num_lmbs = *p++;
        lmbs = (struct of_drconf_cell *)p;

        lmb_found = 0;
        for (i = 0; i < num_lmbs; i++) {
                if (lmbs[i].drc_index == drc_index) {
                        lmb_found = 1;
                        rc = dlpar_remove_lmb(&lmbs[i]);
                        break;
                }
        }

        if (!lmb_found)
                rc = -EINVAL;

        if (rc)
                pr_info("Failed to hot-remove memory at %llx\n",
                        lmbs[i].base_addr);
        else
                pr_info("Memory at %llx was hot-removed\n", lmbs[i].base_addr);

        return rc;
}

#else
static inline int pseries_remove_memblock(unsigned long base,
                                          unsigned int memblock_size)
{
        return -EOPNOTSUPP;
}
static inline int pseries_remove_mem_node(struct device_node *np)
{
        return 0;
}
static inline int dlpar_memory_remove(struct pseries_hp_errorlog *hp_elog)
{
        return -EOPNOTSUPP;
}
static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
{
        return -EOPNOTSUPP;
}
static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
                                        struct property *prop)
{
        return -EOPNOTSUPP;
}
static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
{
        return -EOPNOTSUPP;
}

#endif /* CONFIG_MEMORY_HOTREMOVE */

static int dlpar_add_lmb(struct of_drconf_cell *lmb)
{
        struct memory_block *mem_block;
        unsigned long block_sz;
        int nid, rc;

        if (lmb->flags & DRCONF_MEM_ASSIGNED)
                return -EINVAL;

        block_sz = memory_block_size_bytes();

        rc = dlpar_acquire_drc(lmb->drc_index);
        if (rc)
                return rc;

        /* Find the node id for this address */
        nid = memory_add_physaddr_to_nid(lmb->base_addr);

        /* Add the memory */
        rc = add_memory(nid, lmb->base_addr, block_sz);
        if (rc) {
                dlpar_release_drc(lmb->drc_index);
                return rc;
        }

        /* Register this block of memory */
        rc = memblock_add(lmb->base_addr, block_sz);
        if (rc) {
                remove_memory(nid, lmb->base_addr, block_sz);
                dlpar_release_drc(lmb->drc_index);
                return rc;
        }

        mem_block = lmb_to_memblock(lmb);
        if (!mem_block) {
                remove_memory(nid, lmb->base_addr, block_sz);
                dlpar_release_drc(lmb->drc_index);
                return -EINVAL;
        }

        rc = device_online(&mem_block->dev);
        put_device(&mem_block->dev);
        if (rc) {
                remove_memory(nid, lmb->base_addr, block_sz);
                dlpar_release_drc(lmb->drc_index);
                return rc;
        }

        lmb->flags |= DRCONF_MEM_ASSIGNED;
        return 0;
}

static int dlpar_memory_add_by_count(u32 lmbs_to_add, struct property *prop)
{
        struct of_drconf_cell *lmbs;
        u32 num_lmbs, *p;
        int lmbs_available = 0;
        int lmbs_added = 0;
        int i, rc;

        pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);

        if (lmbs_to_add == 0)
                return -EINVAL;

        p = prop->value;
        num_lmbs = *p++;
        lmbs = (struct of_drconf_cell *)p;

        /* Validate that there are enough LMBs to satisfy the request */
        for (i = 0; i < num_lmbs; i++) {
                if (!(lmbs[i].flags & DRCONF_MEM_ASSIGNED))
                        lmbs_available++;
        }

        if (lmbs_available < lmbs_to_add)
                return -EINVAL;

        for (i = 0; i < num_lmbs && lmbs_to_add != lmbs_added; i++) {
                rc = dlpar_add_lmb(&lmbs[i]);
                if (rc)
                        continue;

                lmbs_added++;

                /* Mark this lmb so we can remove it later if all of the
                 * requested LMBs cannot be added.
                 */
                lmbs[i].reserved = 1;
        }

        if (lmbs_added != lmbs_to_add) {
                pr_err("Memory hot-add failed, removing any added LMBs\n");

                for (i = 0; i < num_lmbs; i++) {
                        if (!lmbs[i].reserved)
                                continue;

                        rc = dlpar_remove_lmb(&lmbs[i]);
                        if (rc)
                                pr_err("Failed to remove LMB, drc index %x\n",
                                       be32_to_cpu(lmbs[i].drc_index));
                }
                rc = -EINVAL;
        } else {
                for (i = 0; i < num_lmbs; i++) {
                        if (!lmbs[i].reserved)
                                continue;

                        pr_info("Memory at %llx (drc index %x) was hot-added\n",
                                lmbs[i].base_addr, lmbs[i].drc_index);
                        lmbs[i].reserved = 0;
                }
        }

        return rc;
}

static int dlpar_memory_add_by_index(u32 drc_index, struct property *prop)
{
        struct of_drconf_cell *lmbs;
        u32 num_lmbs, *p;
        int i, lmb_found;
        int rc;

        pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);

        p = prop->value;
        num_lmbs = *p++;
        lmbs = (struct of_drconf_cell *)p;

        lmb_found = 0;
        for (i = 0; i < num_lmbs; i++) {
                if (lmbs[i].drc_index == drc_index) {
                        lmb_found = 1;
                        rc = dlpar_add_lmb(&lmbs[i]);
                        break;
                }
        }

        if (!lmb_found)
                rc = -EINVAL;

        if (rc)
                pr_info("Failed to hot-add memory, drc index %x\n", drc_index);
        else
                pr_info("Memory at %llx (drc index %x) was hot-added\n",
                        lmbs[i].base_addr, drc_index);

        return rc;
}

static void dlpar_update_drconf_property(struct device_node *dn,
                                         struct property *prop)
{
        struct of_drconf_cell *lmbs;
        u32 num_lmbs, *p;
        int i;

        /* Convert the property back to BE */
        p = prop->value;
        num_lmbs = *p;
        *p = cpu_to_be32(*p);
        p++;

        lmbs = (struct of_drconf_cell *)p;
        for (i = 0; i < num_lmbs; i++) {
                lmbs[i].base_addr = cpu_to_be64(lmbs[i].base_addr);
                lmbs[i].drc_index = cpu_to_be32(lmbs[i].drc_index);
                lmbs[i].flags = cpu_to_be32(lmbs[i].flags);
        }

        rtas_hp_event = true;
        of_update_property(dn, prop);
        rtas_hp_event = false;
}

int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
{
        struct device_node *dn;
        struct property *prop;
        u32 count, drc_index;
        int rc;

        count = hp_elog->_drc_u.drc_count;
        drc_index = hp_elog->_drc_u.drc_index;

        lock_device_hotplug();

        dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
        if (!dn) {
                rc = -EINVAL;
                goto dlpar_memory_out;
        }

        prop = dlpar_clone_drconf_property(dn);
        if (!prop) {
                rc = -EINVAL;
                goto dlpar_memory_out;
        }

        switch (hp_elog->action) {
        case PSERIES_HP_ELOG_ACTION_ADD:
                if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
                        rc = dlpar_memory_add_by_count(count, prop);
                else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
                        rc = dlpar_memory_add_by_index(drc_index, prop);
                else
                        rc = -EINVAL;
                break;
        case PSERIES_HP_ELOG_ACTION_REMOVE:
                if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
                        rc = dlpar_memory_remove_by_count(count, prop);
                else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
                        rc = dlpar_memory_remove_by_index(drc_index, prop);
                else
                        rc = -EINVAL;
                break;
        default:
                pr_err("Invalid action (%d) specified\n", hp_elog->action);
                rc = -EINVAL;
                break;
        }

        if (rc)
                dlpar_free_drconf_property(prop);
        else
                dlpar_update_drconf_property(dn, prop);

dlpar_memory_out:
        of_node_put(dn);
        unlock_device_hotplug();
        return rc;
}

static int pseries_add_mem_node(struct device_node *np)
{
        const char *type;
        const __be32 *regs;
        unsigned long base;
        unsigned int lmb_size;
        int ret = -EINVAL;

        /*
         * Check to see if we are actually adding memory
         */
        type = of_get_property(np, "device_type", NULL);
        if (type == NULL || strcmp(type, "memory") != 0)
                return 0;

        /*
         * Find the base and size of the memblock
         */
        regs = of_get_property(np, "reg", NULL);
        if (!regs)
                return ret;

        base = be64_to_cpu(*(unsigned long *)regs);
        lmb_size = be32_to_cpu(regs[3]);

        /*
         * Update memory region to represent the memory add
         */
        ret = memblock_add(base, lmb_size);
        return (ret < 0) ? -EINVAL : 0;
}

static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
{
        struct of_drconf_cell *new_drmem, *old_drmem;
        unsigned long memblock_size;
        u32 entries;
        __be32 *p;
        int i, rc = -EINVAL;

        if (rtas_hp_event)
                return 0;

        memblock_size = pseries_memory_block_size();
        if (!memblock_size)
                return -EINVAL;

        p = (__be32 *) pr->old_prop->value;
        if (!p)
                return -EINVAL;

        /* The first int of the property is the number of lmb's described
         * by the property. This is followed by an array of of_drconf_cell
         * entries. Get the number of entries and skip to the array of
         * of_drconf_cell's.
         */
        entries = be32_to_cpu(*p++);
        old_drmem = (struct of_drconf_cell *)p;

        p = (__be32 *)pr->prop->value;
        p++;
        new_drmem = (struct of_drconf_cell *)p;

        for (i = 0; i < entries; i++) {
                if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
                    (!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
                        rc = pseries_remove_memblock(
                                be64_to_cpu(old_drmem[i].base_addr),
                                                     memblock_size);
                        break;
                } else if ((!(be32_to_cpu(old_drmem[i].flags) &
                            DRCONF_MEM_ASSIGNED)) &&
                            (be32_to_cpu(new_drmem[i].flags) &
                            DRCONF_MEM_ASSIGNED)) {
                        rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
                                          memblock_size);
                        rc = (rc < 0) ? -EINVAL : 0;
                        break;
                }
        }
        return rc;
}

static int pseries_memory_notifier(struct notifier_block *nb,
                                   unsigned long action, void *data)
{
        struct of_reconfig_data *rd = data;
        int err = 0;

        switch (action) {
        case OF_RECONFIG_ATTACH_NODE:
                err = pseries_add_mem_node(rd->dn);
                break;
        case OF_RECONFIG_DETACH_NODE:
                err = pseries_remove_mem_node(rd->dn);
                break;
        case OF_RECONFIG_UPDATE_PROPERTY:
                if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
                        err = pseries_update_drconf_memory(rd);
                break;
        }
        return notifier_from_errno(err);
}

static struct notifier_block pseries_mem_nb = {
        .notifier_call = pseries_memory_notifier,
};

static int __init pseries_memory_hotplug_init(void)
{
        if (firmware_has_feature(FW_FEATURE_LPAR))
                of_reconfig_notifier_register(&pseries_mem_nb);

        return 0;
}
machine_device_initcall(pseries, pseries_memory_hotplug_init);